在sqlnet.ora文件中将tcp.validnode_checking的值设为no。然后重v刹启数据库与服务就可以了。

MOS上面解释
Oracle E-Business Suite Release 11.5.10 introduced support for the Oracle Net security feature, tcp.validnode_checking, which is used to prevent unauthorized Oracle Net access (for example via SQL*Plus) to the Applications database. If a node or PC is not registered, the connection attempt will fail with the error ORA-12537: TNS: connection closed.

第一种方法
第一种
在sqlnet.ora文件中将tcp.validnode_checking的值设为no。然后重v刹启数据库与服务就可以了。

第二种方法
客户，在使用pl/sql连接数据库的时候提示ORA-12537：TNS:连接关闭。
查看过程：
1）查看客户端tnsname.ora文件信息如下：# tnsnames.ora Network Configuration File: E:\oracle\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.
RHYS =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.20.1)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = test)
)
)
没有问题
2）查看服务器监听状态
[oracle@oracle-one ~]$ lsnrctl status
LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 01-NOV-2013 11:19:35Copyright (c) 1991, 2013, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=oracle-one)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.4.0 - Production
Start Date 01-NOV-2013 11:08:41
Uptime 0 days 0 hr. 10 min. 54 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Listener Log File /opt/app/oracle/diag/tnslsnr/oracle-one/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=oracle-one)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
Services Summary...
Service "test" has 1 instance(s).
Instance "test", status READY, has 1 handler(s) for this service...
Service "RHYSXDB" has 1 instance(s).
Instance "test", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@oracle-one ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.4.0 Production on Fri Nov 1 11:19:38 2013Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> show parameter service NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string test
SQL>
正常
3）在客户端使用tnsping：
C:\Users\Administrator>tnsping rhysTNS Ping Utility for 32-bit Windows: Version 11.2.0.1.0 - Production on 01-11月-
2013 11:10:05Copyright (c) 1997, 2010, Oracle. All rights reserved.已使用的参数文件:
E:\softsetup\oracle_client\oracle_base\network\admin\sqlnet.ora
已使用 TNSNAMES 适配器来解析别名
尝试连接 (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.1
68.20.1)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = test)))
TNS-12547: TNS: 丢失连接
C:\Users\Administrator>
4）在服务器查看sqlnet.ora文件内容如下：
tcp.validnode_checking=yes
tcp.invited_nodes=(192.168.56.101)
可以看出，正是由于存在tcp.validnode_checking=yes才去检查tcp.invited_nodes定义的节点，将客户端ip地址192.168.56.1加入该文件中即可。
tcp.validnode_checking=yes
tcp.invited_nodes=(192.168.56.101,192.168.56.1)
"sqlnet.ora" 1118L, 32887C written
[oracle@oracle-one admin]$
由于操作的是正在运行的服务器，，因此不能重启该监听，但是reload可以实现。
[oracle@oracle-one admin]$
lsnrctlLSNRCTL for Linux: Version 11.2.0.4.0 - Production on 01-NOV-2013 11:22:57Copyright (c) 1991, 2013, Oracle.
All rights reserved.Welcome to LSNRCTL, type "help" for information.
LSNRCTL> help
The following operations are available
An asterisk (*) denotes a modifier or extended command:start stop status
services version reload
save_config trace spawn
change_password quit exit
set* show* LSNRCTL> reload
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=oracle-one)(PORT=1521)))
The command completed successfully
LSNRCTL> exit
5）在客户端测试：
C:\Users\Administrator>tnsping rhys
TNS Ping Utility for 32-bit Windows: Version 11.2.0.1.0 - Production on 01-11月-
2013 11:23:14Copyright (c) 1997, 2010, Oracle. All rights reserved.已使用的参数文件:
E:\softsetup\oracle_client\oracle_base\network\admin\sqlnet.ora
已使用 TNSNAMES 适配器来解析别名
尝试连接 (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.1
68.56.101)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = RHYS)))
OK (10 毫秒)C:\Users\Administrator>
问题得到解决

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